Apparatus for proportioning and mixing particulate materials

ABSTRACT

Apparatus for proportioning and mixing particulate or granular material and particularly for handling plastic granular material constituting the various ingredients of a granular plastic mixture or blend of material adapted to be fed into plastic extruders, blow molding plastic forming machines, or the like. The apparatus of a basic embodiment disclosed includes at least one rotary type metering unit adapted for metering the major part or portion of the granular plastic mixture or blend and includes a smaller rotary metering unit having adjustable socket-like chambers adapted to receive a certain quantity of granular material and to dispense the material at a substantially constant rate as the apparatus is operated. Another embodiment disclosed includes a vertically reciprocating plunger having recess means defining a measuring chamber adapted to measure a certain quantity of material and at a certain rate. The embodiment of the invention utilizing the plunger type metering means is particularly useful for metering color concentrate pellets or granules in the proportioning of the plastic granule mixture or blend. The plunger is adapted to be vertically reciprocated either by direct mechanical action utilizing a multi-lobe cam for direct vertical reciprocation of the plunger or may be pneumatically operated through a timed air valve synchronously connected with one of the large volume rotary metering means dispensing another ingredient of the plastic granule mixture.

United States Patent [451 July 25, 1972 [72] Inventor: Gerald T.Aldridge, 4500 Dearing Rd,

Memphis, Tenn. 38117 [22] Filed: Sept. 5, 1968 [21] Appl.No.: 757,564

[52] U.S. Cl ..222/l36, 222/410 [51] Int. Cl ..B67d 5/48 [58] Field ofSearch ..222/507, 509, 161, 145, 448, 222/453, 136, 368, 309, 142, 138,410; 137/602 [56] References Cited UNITED STATES PATENTS 651,010 6/1900Galloway ..222/145 2,684,785 7/1954 Waldorf et a1. ...222/l42 X2,792,156 5/1957 Camp ..222/309 3,160,318 12/1964 Steiner et a1. 222/365X 3,227,325 1/1966 Bates 222/309 3,244,328 4/1966 Brown 222/1363,367,544 2/1968 Formando ..222/368 Primary ExaminerRobert B. Reeves[57] ABSTRACT Apparatus for proportioning and mixing particulate orgranular material and particularly for handling plastic granularmaterial constituting the various ingredients of a granular plasticmixture or blend of material adapted to be fed into plastic extruders,blow molding plastic forming machines, or the like.

The apparatus of a basic embodiment disclosed includes at least onerotary type metering unit adapted for metering the major part or portionof the granular plastic mixture or blend and includes a smaller rotarymetering unit having adjustable socket-like chambers adapted to receivea certain quantity of granular material and to dispense the material ata substantially constant rate as the apparatus is operated.

Another embodiment disclosed includes a vertically reciprocating plungerhaving recess means defining a measuring chamber adapted to measure acertain quantity of material and at a certain rate. The embodiment ofthe invention utilizing the plunger type metering means is particularlyuseful for metering color concentrate pellets or granules in theproportioning of the plastic granule mixture or blend. The plunger isadapted to be vertically reciprocated either by direct mechanical actionutilizing a multi-lobe cam for direct vertical reciprocation of theplunger or may be pneumatically operated through a timed air valvesynchronously connected with one of the large volume rotary meteringmeans dispensing another ingredient of the plastic granule mixture.

2 Claims, 6 Drawing Figures PATENTEDJMS m2 SHEET 3 BF 3 GERALD T ALDRl065 APPARATUS FOR PROPORTIONING AND MIXING PARTICULATE MATERIALSBACKGROUND OF THE INVENTION 1. Field of the Invention Relates generallyto apparatuses for proportioning dry bulk granular or particulateingredient materials in forming a formulated blend or mixture. Theapparatus is particularly intended for proportioning or mixing new,reground, used, and color concentrate plastic granules or pellets informing a blend or mixture adapted to be fed into a plastic blow moldingmachine, plastic extruder type machine, or the like.

2. Description of the Prior Art Granular plastic material proportioningapparatus with which I am familiar proportions the several ingredientsof a plastic mixture by intermittently cyclically dumping measuredquantities of the material into a common hopper or bin. US. Pat. No.3,312,374 issued Apr. 4, 1967, discloses plastic granule metering andmeasuring apparatus of the above-mentioned type. The metering andmeasuring apparatus of US. Pat. No. 374 includes a plurality of meteringunits each being adapted to meter or measure a granular ingredient ofthe plastic blend or mixture. The machine includes an air cylinder forvertical reciprocation of the measuring means and a mixture is compiledby intermittently dumping the ingredients. A disadvantage of themetering and measuring apparatus of US. Pat. No. 374 is that the outputof the apparatus is somewhat limited by the intermittent reciprocativemovement or principle of operation of the apparatus.

SUMMARY OF THE INVENTION The preferred embodiment of the apparatus ofthe present invention includes rotary type material dispensing means andsuch means adapted for dispensing or metering the granular plasticmaterial at a selected substantially constant rate. The plastic granulesof the several ingredients of a granular plastic mix may be smoothly andsubstantially continuously metered or dispensed into a common hopper asnormal gravitational action on the plastic granules. The proportion ofeach ingredient of the granular plastic mix may be accurately controlledin the following manner: I By regulating the speed or rate of actuationrelatively between two or more ingredientdispensing units of theapparatus and (2) by adjusting or regulating the volume of the colorconcentrate plastic granules dispensed by the color concentrate unit.

In plastic blow molding or extruding operations it is desirable to mix aproportion of virgin or new pellets or granules to a proportion ofreground pellets or granules and also to mix a small proportion of colorconcentrate granules to the new and reground pellet ingredients. Acommon plastic granule mixture may be 49 percent virgin material, 49%reground or used material and 2 percent color concentrate material. Theaction of the present invention is such that the materials may bedispensed from each ingredient dispensing unit at a selectedsubstantially constant rate and without intermittent or periodic action.The substantially constant or continuous flow of materialthrough theapparatus increases substantially its total output as compared withprior art cycling apparatus and provides an apparatus of substantiallygreater capacity. The proportioning and mixing apparatus of the presentinvention is also less complex than comparable prior art apparatus andis cheaper to manufacture and maintain.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of theproportioning and mixing ap- FIG. 6 is a vertical plane sectional viewtaken as on the line VIVI of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of theinvention is indicated by numeral 11 and shown in FIGS. 1 and 2 andincludes basically the following parts: Primary ingredient meansincluding first, second and third metering units 13, 15, 17 each adaptedrespectively for metering an ingredient of the granular plastic materialmix M; secondary ingredient metering means including a metering unit 19;motor means 21; first drive means 23 operably connecting motor means 21and primary ingredient metering unit 13; second drive means 25 operablyconnecting primary ingredient metering unit 13 and secondary ingredientmetering unit 19; and third drive means 27, 29 interconnectingrespectively primary ingredient metering means 13, 15, 17.

The primary ingredient means including metering units 13, l5, 17 areoperable for metering the body or major portion of mixture M. It will beunderstood that the number of primary ingredient metering units l3, 15,17 may be varied to suit the particular application of the invention. Inmost cases only two of the units will be provided, namely, unit 13 fordispensing virgin pellet or granular plastic material and unit 15 fordispensing reground pellet or granular plastic material. Unit 17 will beprovided, if desired, for dispensing a different type of plastic. Thematerial dispensed by units 13, 15, 17 constitutes the main body portionof the granular plastic mix M.

Secondary metering unit 19 is a unit of less capacity than each ofprimary ingredient units 13, 15, 17 and is adapted for metering colorconcentrate pellets or granules indicated S.

Primary ingredient metering units 13, I5, 17 preferably are alike insize and configuration and each is generally in the form of a rotarytype feeder or dispensing mechanism. Metering unit 13 includes a rotor31 journalled on bearings 33 in housing structure 35. Rotor 31 includesa plurality of equiangularly arranged blades projecting radially from ashaft 39 mounted in bearings 33. Housing 35 is open vertically andincludes an intermediate portion which houses rotor 31 and such portiondefining an interior plane curve surface 41 arranged in close tolerancerelationship with the path of the distal edge portions of rotor blades37 (see FIG. 2). Housing 35 includes structure defining an intakeopening 43 and a discharge opening 45 respectively arranged directlyover and under rotor 31 and adapted respectivelyfor conducting primaryingredient granules P through rotor 31 and housing structure 35. Rotor31 is adapted to move clockwise, as viewed in FIG. 2, and to meter 21measured quantity of granules P through discharge opening 45; each ofthe troughlike spaces 47 between adjacent blades 37 of rotor 31 isadapted to contain a measured quantity of granules P and to convey thegranules in an arced movement through housing 35. Hopper structure 49arranged upwardly and circumferentially around discharge opening 45 ofhousing 35 is adapted to temporarily hold a quantity of granules P; thegranules are adapted to be held in hopper structure 49 and to be feddownwardly through opening 43, through rotor 31 and discharge opening45.

First drive means 23 preferably includes drive and driven sprocketwheels 51, 53 fixedly secured respectively on motor shaft 55 and rotorshaft 39 and includes a chain 57 drivingly coupling the sprocket wheels.Prime mover 21 preferably is of a variable speed type unit, as forexample, a motor reducer combination with an electrical clutch adaptedfor driving rotor 31 at a selected constant speed.

Primary ingredient metering units l5, 17 each are alike and correspondsubstantially with metering unit 13 and include respectively rotormembers 59, 61; bearing means 63, 65, housing means 67, 69 havingrespectively intake and discharge openings 73, 75, 77, 79; rotor shafts81, 83; and hopper structure 85, 87. Metering unit 15 is adapted forconveying and metering reground plastic granule material P from hopperstructure 85 downwardly through rotor 59 and discharge opening 77. Inlike manner, metering unit 17 is adapted for metering and conveying adifferent type plastic granule material P downwardly from hopperstructure 87, through rotor 61 and downwardly through discharge opening79. A large mixing hopper 88 is subjacently arranged respectively underthe discharge openings of metering units 13, 15, 17 and is adapted forreceiving and mixing primary ingredient granules P issuing from meteringunit 13, 15, 17 into mixture M which passes outwardly through spout 89for further processing. Hopper 88 is provided with a curved and slopingfunnel-like portion 90 directly below metering units 13, l5, 17, 19which has an aperture 91 in the bottOm thereof through which the mixtureM passes downwardly to 1 spout 89 so that the granules or pellets willbe well mixed. Although not shown in the other embodiments depicted inFIGS. 3 6, it will be understood that if desired the same type portionas portion 90 with aperture 91 may be provided.

Third drive means 27 interconnecting first and second metering units 13,in positive drive connection preferably in cludes chain and sprocketmeans 93, 95, 97. In like manner, third drive means 29 interconnectingfirst and third metering units l3, 17 preferably includes chain andsprocket drive means 99, 101, 103. The chain and sprocket means of thirddrive means 27, 29 are adapted to be adjustably manipulated respectivelyfor adjusting or varying the ratio of rotation respectively betweenfirst and second metering units 13, 15 and second and third meteringunits 13, 17. Also, by adjustably manipulating the chain and sprocketmeans respectively of third drive means 27, 29 the ratio or rate ofmetering respectively between metering units 15, 17 may be varied; byadjusting the ratio respectively between either or both drive means 27,29 the first, second and third metering units 13, 15, 17 may be adjustedfor dispensing desired proportions or ingredients of mixture M.

Secondary ingredient metering means adapted for metering the colorconcentrate granules S in apparatus 11 is a rotary type unit andincludes a disk-like metering rotor 105 mounted on rotor shaft 107rotatively secured in housing 109 on bearings 111. Hopper structure 113superjacently secured on housing 109 is adapted to temporarily holdsecondarY ingredient granules S for feeding the granules throughmetering rotor 105 and downwardly through discharge opening 115 ofhousing 109. Rotor 105 preferably is provided with a plurality ofsocketlike measuring chambers 117 opening radially out wardly anduniformly spaced about the circumferential periphery of rotor 105. Thebottom of each measuring chamber 117 is preferably adjustable radiallyof rotor 105 and preferably formed substantially by adjustable plugs 119threadedly secured respectively in threaded bore openings extendingradially in rotor 105.

Upon clockwise rotation of rotor 105 (as viewed in FIG. 2), theplurality of metering chambers 117 are adapted to sequentially be incommunication respectively with intake opening 121 and discharge opening115 of housing 109. Each measuring chamber is adapted to be incommunication alternatingly cyclically with the intake and dischargeopenings of housing 109 and to convey a measured amount of granules Sthrough metering unit 19. Uniformly adjustably manipulating respectivelyplugs 119 regulates the capacity or output of metering unit 19.

Second drive means preferably includes chain and sprocket wheel means123, 125, 127 connecting in positive drive connection, rotor shaft 107of secondary ingredient metering unit 19 with rotor shaft 39 of primaryingredient metering unit 13. Swapping sprocket wheels 127, 125respectively on shafts 39, 107, or changing the effective diametersrespectively of the sprocket wheels changes the speed of rotor 105 ofmetering unit 19 or the relative speed of rotor 105 and rotor 31 foradjusting the output of metering unit 19.

Secondary ingredient granules S dropping from discharge opening 115falls on funnel-like portion 90 of mixing hopper 89. Granules S aregravitatingly conveyed downwardly in portion 90 and are mixed withgranules P issuing from primary ingredient metering units 13, 15, 17 andform mixture M. The

mixture is conducted through aperture 91 and spout 89 for heating andmelting or for further processing.

By adjustably regulating the rotor speeds respectively of first, secondand third primary ingredient metering units 13, 15, 17 and secondaryingredient metering unit 19 and by ad justably varying the volume ofmeasuring chambers 117 of rotor of metering unit 19 a desired mixture Mmay be obtained. It will be understood that in certain embodiments ofthe invention it may be desirable to utilize positive drive stepped beltand pulley means in lieu of the chain and sprocket means respectively offirst and second drive means 23, 25 and third drive means 27, 29. Also,other drive means including meshed gear drive means may provide suitablepositive power transmission means respectively between the meteringunits.

Apparatus 129, illustrated in FIGS. 3 and 4, illustrates a secondembodiment of the invention. Apparatus 129 differs substantially fromapparatus 11 in that the color concentrate metering means utilizesreciprocating plunger means rather than the rotating disk rotor (105) ofthe secondary ingredient metering unit 19) of apparatus 1 1.

Apparatus 129 basically includes primary ingredient metering meansincluding first and second rotary metering units 131, 133; secondaryingredient metering means including a reciprocating type metering unit135; motor or prime mover means 137; first, second and third drive means139, 141, 143 and mixing hopper means 145.

Primary ingredient metering units 131, 133 each are alike and correspondsubstantially with a primary ingredient metering unit of apparatus 11.Metering units 131, 133 includes respectively rotor means 147, 149;housings 151, 153; and hopper structure 155, 157 secured superjacentlyrespectively on housings 151, 153 adapted for holding and feedinggranules P respectively through rotors 147, 149.

First drive means 139 including chain and sprocket means 159, 161, 163drivingly interconnect prime mover means 137 with first metering unit131. In like manner, third drive means 141 including chain and sprocketmeans 165, 167, 169 operatively interconnect respectively first andsecond metering units 131, 133.

Secondary ingredient metering unit 135 includes a housing 171, hopperstructure 173 superjacently secured on housing 171 and a meteringplunger 175 vertically reciprocatingly fitted in bore 177 of housing171. Shank portion 179 of plunger 175 is reciprocatingly fitted inbushing 181 fixedly secured respectively superjacently on inclined apronportion 183 of mixing hopper 145. The upper portion of plunger 175includes a mushroom-like head 185 defining the upper terminus of theplunger and an annular nut-like cuff 187 threadedly secured subjacentlyof head 185 on plunger shank 179. The relative vertical dispositionrespectively of head and cuff portion 185, 187 of plunger 175 isadjustable for regulating the volume of plunger measuring chamber 189.Cuff and head portions 185, 187 of plunger 175 are of like diameter andsnugly but freely fitted in bore 177 of housing 171. Vertical upwardmovement of plunger 175 causes head 185 to move upwardly past intakeopening 191 of housing 171 and permits measuring chamber 189 to befilled with secondary ingredient granules S. Downward movement ofplunger 175 moves cuff 187 below discharge opening 193 of housing 171and permits granules S to be discharged onto apron 183 of mixing hopper145.

Second drive means 141 operably interconnecting secondary ingredientmetering plunger 175 and primary ingredient metering unit 131 includes ahorizontally journalled plunger drive shaft 195 stationarily journalledon support structure 197; a crank wheel 199 fixedly secured on an end ofshaft 195; a connecting rod 201 articulatingly secured respectively atupper and lower end portions 203, 205 to the lower end of plunger shank179 and the throw journal of crank wheel 199; and chain and sprocketmeans 207, 209, 211 connecting in positive drive connection rotor shaft213 of first metering unit 131 and plunger drive shaft 195.

In addition to regulating the output of secondary ingredient meteringunit 135 by regulating the speed of reciprocation of plunger 175, theoutput of metering unit 135 may be adjusted by regulating the volume ofmeasuring chamber 189: tumably manipulating cut? 187 of plunger 175upwardly or downwardly on shank 179 decreases or increases respectivelythe volume of measuring chamber 189 and regulates the quantity of colorconcentrate granules S metered by unit 135.

Apparatus 215 illustrated in FIGS. 5 and 6 is a third embodiment of theinvention. Apparatus 215 basically includes primary ingredient meteringmeans including first and second metering unIts 217, 219; secondaryingredient metering means including a metering unit 221; first drivemeans 223 operably interconnecting motor or prime mover means 225 andfirst metering unit 217; and second and third drive means 227, 229interconnecting first metering unit 217 respectively with secondaryingredient metering unit 221 and primary ingredient metering unit 219.

Primary ingredient metering units 217, 219 each are alike and correspondsubstantially in structure and function with metering units 131, 133 ofapparatus 129. Metering units 217, 219 include respectively rotor means231, 233; housing means 235, 237; and hopper structures 239, 241superjacently fixedly secured respectively on housing structures 235,237. In like manner, secondary ingredient metering unit 221 of apparatus215 corresponds substantially with metering unit 135 of apparatus 129and includes a metering plunger 243 vertically reciprocatingly receivedin a bore 245 in a housing 247 and includes bushing means 249 guidinglyconstraining plunger shank 251. The upper end of plunger 243'includeshead and cuff portions 253, 255 defining an annular measuring chamber257. Threadedly manipulating cuff 255 axially on shank 251 is adaptedfor adjustably regulating the volume of measuring chamber 257 and theoutput of color concentrate granules.

First drive means 223 preferably includes chain and sprocket means 259,261, 263 defining positive drive connection between prime mover means225 and primary ingredient metering unit 217. Third drive means 229preferably includes chain and sprocket means 265, 267, 269interconnecting first and second metering units 217, 219.

Second drive means 227 interconnects in synchronized drive rotor 231 ofprimary ingredient metering unit 217 and plunger 243 of secondaryingredient metering unit 221. Second drive means 227 includes adouble-acting pistoncylinder assembly 271 stationarily secured onsupport structure 273; coupling means 275 coupling piston rod 277 ofpiston-cylinder assembly 271 with plunger shank 251; an air supply line279 connectable with a supply of compressed air; conduit means 281, 283,285 interconnecting supply line 279 with piston-cylinder assembly 271; areciprocative type air valve 287 interposedly arranged in conduit means281, 283, 285; and cam operative actuating means 289 operativelyinterconnecting rotor 231 of metering unit 217 and air valve 287 forcausing synchronous movement of plunger 243 and rotor 231. Up and downmovement of the barrel or movable port parts (not shown) of air valve287 causes air in conduit 21 to be directed through either conduit 283or conduit 285 respectively for raising and lowering joined piston 291and plunger 243. ExhaUst air of air valve 287 is exhausted through ports293, 295.

Actuating means 289 controls air valve 287 and the up and down movementof plunger 243. Actuating means 289 preferably includes a multi-lobedcam 297 secured on rotor shaft 299 of metering unit 217 and includesfollower rod and spring means 301, 303 operably interconnecting cam 297and air valve 287. Up and down reciprocative movement of follower rod301 causes compressed air to be directed alternatingly through conduits283, 285 respectively on opposite sides of piston 291 and causesvertical reciprocation of plunger 243. With each up and down movement ofplunger 243 a measured quantity of secondary ingredient granules isreceived in and discharged from measuring chamber 257.

Granules discharged from plunger measuring chamber 257 drop on inclinedapron 305 of mixing hopper 307. The primary and secondary ingredientgranules issuing respectively from primary ingredient metering units217, 219 and secondary metering unit 221 are received and mixed inmixing hopper 307. The mixed granules are conducted through spout 309for further processing.

lclaim:

1. Apparatus for proportioning and mixing particulate or granularprimary and secondary plastic ingredient materials for making a mixtureof granular plastic material suitable for further processing comprisingprimary granular ingredient metering means for metering virgin orreground plastic granules used in forming the body or major mass part ofthe granular plastic mixture, said primary ingredient metering meansincluding at least one primary ingredient metering unit including aradially bladed horizontally journalled rotor, housing structuredefining intake and discharge openings respectively superjacently andsubjacently of said rotor, prime mover means for powering said rotor,first drive means interconnecting said prime mover means and said rotorfor driving said rotor at a selected constant speed, said primaryingredient metering unit upon rotation of said rotor being operative formetering a certain quantity of granular primary ingredient materialgravitatingly downwardly through said rotor and out of said dischargeopening of said housing structure, secondary ingredient metering meansfor metering color concentrate granules for use in coloring the majormass part of the mixture of the primary granular ingredient issuing fromthe discharge opening of said primary ingredient metering unit, saidsecondary ingredient metering means including a metering member havingstructure defining at least one small measuring chamber of a certainvolume adapted to be filled and emptied cyclically alternatingly ofcolor concentrate granules, housing structure arranged about saidmetering member defining intake and discharge openings arrangedrespectively contiguous of the measuring chamber of said meteringmember, mechanical action means for guidingly constraining said meteringmember in continuous cyclic movement and for movement of said measuringchamber into and out of communication alternatingly cyclically with saidintake and discharge openings of said secondary ingredient meteringmeans housing structure, second drive means interconnecting in driveconnection the rotor of said primary ingredient metering unit and themetering member of said secondary metering means, said secondarymetering means being adapted for metering a specific quantity ofgranular color concentrate ingredient material cyclically into and outof the metering member chamber upon each revolution of said primarymetering unit rotor and downwardly gravitatingly out of the dischargeopening of said secondary ingredient metering means, and mixing hoppermeans arranged underneath said discharge openings respectively of saidprimary and secondary ingredient metering means for receiving thegranular material issuing from said discharge openings and for mixingthe primary and secondary granular ingredient material into aproportioned mixture; said metering member means of said secondaryingredient metering means including a metering plunger, recess structuredefining an annular measuring chamber arranged concentrically about theaxis of said plunger, said means guidingly constraining said meteringplunger including stationary bushing means mounting said plunger in avertical disposition substantially subjacently of said discharge openingof said secondary ingredient metering means, said metering plunger beingadapted to vertically move upwardly to fill said measuring chamber withplastic granules and to move downwardly to release the measuredquantities of granules through said discharge opening downwardly intosaid hopper means, and wherein said second drive means interconnectingthe rotor of said primary ingredient metering unit and said meteringplunger includes a double-acting piston-cylinder assembly stationarilymounted subjacently of said plunger, link means interconnecting thelower end of said plunger with the piston of said piston-cylinderassembly for common vertical reciprocal movement of said piston andplunger, an air supply line connectable with a source of compressed air,conduit means interconnecting said air supply line and saidpiston-cylinder assembly, air valve means interposedly arranged in saidair conduit means for directing compressed air to one side or the otherside of the piston of said piston-cylinder assembly respectively foreither raising or lowering said metering plunger, and includingactuating means operatively interconnecting said rotor and said airvalve means for causing synchronous reciprocating movement of saidplunger with rotative movement of said rotor.

2. The apparatus of claim 1 wherein said air valve means isreciprocatingly operative for movement between a first position fordirecting air on one side of the piston of said pistoncylinder assemblyand a second position for directing air on the other side of saidpiston, and wherein said actuating means includes a cam operativelypositively drivingly connected with said rotor of said primaryingredient metering means, said cam having a plurality of lobesintermittently spaced about the circumferential periphery of said camand arranged along a common plane of rotation, and including followerrod means operatively interposedly engageable between said cam lobes andsaid valve means for actuating said valve means to said first positionwhen said follower rod is moved to a first osition by a lobe of said camand includes follower rod spring means for urging said rod against saidcam at the minimum diameter of said cam and said valve to said secondposition, said cam being operative for causing substantially continuousalternating movement of said valve means between said first and secondpositions respectively for raising and lowering said metering plunger ofsaid secondary metering means and for cyclically metering materialdownwardly and into said mixing hopper means.

1. Apparatus for proportioning and mixing particulate or granularprimary and secondary plastic ingredient materials for making a mixtureof granular plastic material suitable for further procesSing comprisingprimary granular ingredient metering means for metering virgin orreground plastic granules used in forming the body or major mass part ofthe granular plastic mixture, said primary ingredient metering meansincluding at least one primary ingredient metering unit including aradially bladed horizontally journalled rotor, housing structuredefining intake and discharge openings respectively superjacently andsubjacently of said rotor, prime mover means for powering said rotor,first drive means interconnecting said prime mover means and said rotorfor driving said rotor at a selected constant speed, said primaryingredient metering unit upon rotation of said rotor being operative formetering a certain quantity of granular primary ingredient materialgravitatingly downwardly through said rotor and out of said dischargeopening of said housing structure, secondary ingredient metering meansfor metering color concentrate granules for use in coloring the majormass part of the mixture of the primary granular ingredient issuing fromthe discharge opening of said primary ingredient metering unit, saidsecondary ingredient metering means including a metering member havingstructure defining at least one small measuring chamber of a certainvolume adapted to be filled and emptied cyclically alternatingly ofcolor concentrate granules, housing structure arranged about saidmetering member defining intake and discharge openings arrangedrespectively contiguous of the measuring chamber of said meteringmember, mechanical action means for guidingly constraining said meteringmember in continuous cyclic movement and for movement of said measuringchamber into and out of communication alternatingly cyclically with saidintake and discharge openings of said secondary ingredient meteringmeans housing structure, second drive means interconnecting in driveconnection the rotor of said primary ingredient metering unit and themetering member of said secondary metering means, said secondarymetering means being adapted for metering a specific quantity ofgranular color concentrate ingredient material cyclically into and outof the metering member chamber upon each revolution of said primarymetering unit rotor and downwardly gravitatingly out of the dischargeopening of said secondary ingredient metering means, and mixing hoppermeans arranged underneath said discharge openings respectively of saidprimary and secondary ingredient metering means for receiving thegranular material issuing from said discharge openings and for mixingthe primary and secondary granular ingredient material into aproportioned mixture; said metering member means of said secondaryingredient metering means including a metering plunger, recess structuredefining an annular measuring chamber arranged concentrically about theaxis of said plunger, said means guidingly constraining said meteringplunger including stationary bushing means mounting said plunger in avertical disposition substantially subjacently of said discharge openingof said secondary ingredient metering means, said metering plunger beingadapted to vertically move upwardly to fill said measuring chamber withplastic granules and to move downwardly to release the measuredquantities of granules through said discharge opening downwardly intosaid hopper means, and wherein said second drive means interconnectingthe rotor of said primary ingredient metering unit and said meteringplunger includes a double-acting piston-cylinder assembly stationarilymounted subjacently of said plunger, link means interconnecting thelower end of said plunger with the piston of said pistoncylinderassembly for common vertical reciprocal movement of said piston andplunger, an air supply line connectable with a source of compressed air,conduit means interconnecting said air supply line and saidpiston-cylinder assembly, air valve means interposedly arranged in saidair conduit means for directing compressed air to one side or the otherside of the piston of said piston-cylinder assembly respectively foreither raising or lowering said metering plunger, and includingactuating means operatively interconnecting said rotor and said airvalve means for causing synchronous reciprocating movement of saidplunger with rotative movement of said rotor.
 2. The apparatus of claim1 wherein said air valve means is reciprocatingly operative for movementbetween a first position for directing air on one side of the piston ofsaid piston-cylinder assembly and a second position for directing air onthe other side of said piston, and wherein said actuating means includesa cam operatively positively drivingly connected with Said rotor of saidprimary ingredient metering means, said cam having a plurality of lobesintermittently spaced about the circumferential periphery of said camand arranged along a common plane of rotation, and including followerrod means operatively interposedly engageable between said cam lobes andsaid valve means for actuating said valve means to said first positionwhen said follower rod is moved to a first position by a lobe of saidcam and includes follower rod spring means for urging said rod againstsaid cam at the minimum diameter of said cam and said valve to saidsecond position, said cam being operative for causing substantiallycontinuous alternating movement of said valve means between said firstand second positions respectively for raising and lowering said meteringplunger of said secondary metering means and for cyclically meteringmaterial downwardly and into said mixing hopper means.